Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
  • C08G69/36—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from amino acids, polyamines and polycarboxylic acids

Definitions

• This invention relates to synthetic linear polyamides, and more particularly to a new interpolyamide possessing unusual and valuable properties.
• the fiber-forming or linear polyamides to which this invention relates are in general high melting products of pronounced crystallinity and insolubility in most solvents except mineral acids, formic acid, and the phenols. Although these properties, together with those of great strength and excellent elasticity, are highly valuable in the manufacture of textile fibers, these same properties make it diflicult to prepare clear sheets, coating compositions, and other products which require the use of solvents beyond the restricted range mentioned above.
• valuable fiber-forming polyamides can be obtained by the polymerization of G-aminocaproic acid or its amide-forming derivatives. ,As ordinarily carried out, this reaction yields about 75% polymer and 25% of caprolactam. It is further known that valuable fiber-forming polyamides can be prepared from the reaction of hexamethylenediamine with a substantially equimolecular quantity of adipic acid or an amide-forming derivative thereof. Both of these polyamides ar characterized by high and sharp melting points (210 C. and 264 C. respectively, in a glass tube in absence of oxygen) and by insolubility in most solvents. Phenols and certain acids are practically the only solvents for these polymers.
• This invention has as an object the preparation of linear interpolyamides, which in addition to being fiber-forming have properties of improved solubility, lower and generally wider melting range, lessened crystallinity, and a more resin-like character which confers to the new interpolyamides a wider utility in the arts than heretofore possible with other polyamides.
• a further object is to prepare from G-aminocaproic acid as one component interpolyamides low in lactam component. Other objects will appear hereinafter.
• the preferred procedure for preparing the interpolymers of this invention consists in heating the reactants in a closed system with retention of the water of reaction until substantially all the reactants have combined to form polymer. Under these conditions the caprolactam formed as an initial by-product in the reaction is converted into polymer, probably through intermediate hydrolysis to aminocaproic acid. Indeed, it is preferable to add water to the original reactants, e. g., 5-50% based on the weight of the reactants, in carrying out the initial polymerization. This is particularly true when the interpolymers are prepared directly from caprolactam as the. amino acid constituent. After the initial heating with retention of water, e. g., in a closed system or under superatmospheric pressure, the heating is continued with removal of water until a product of the desiredproperties is obtained.
• the reaction is continued until a test portion indicates that the product can b formed into pliable fibers.
• Another method of following the course of the reaction is to determine the intrinsic viscosity of the polymer as defined in U. S. Patent 2,130,948.
• the reaction is continued until the intrinsic viscosity is at least 0.4 and preferably at least 0.6, since the strength and toughness of the product presence of water, it is desirable to evacuate the reaction mixture while in the molten state at the end of the heating cycle. In this manner, the lactam content can be lowered to below 3%.
• Exnnmn I A mixture of 6 parts of G-aminocaproic acid (M. P. 201-203 C.) and 4 parts of hexamethylene diammonium adipate (salt derived from hexamethylenediamine and adipic acid) was heated in an evacuated, sealed tube for 2 hours at 210-230 C. The low molecular weight polymer thus obtained was heated for 2 hours more at 220-240' C. imder a pressure of 2 mm. The interpolyamide obtained was an opalescent, tough, pseudo-resinous solid. It had an intrinsic viscosity of 0.98 and, on a heated metal block, fibers of the interpolymer melted over the range 01' 155-160' C.
• the interpolymer was soluble in formic acid, phenol, and hot glacial acetic acid. Unlike either polyhexamethylene adipamide or the polyamide from fi-aminocaproic acid, the interpolymer was soluble in hot butanol and mixtures of alcohols with halogenated hydrocarbons, such as methanol-chloroform, methanol-betatrichloroethane, and methanol-trichloroethylene mixtures. Unsaturated alcohols, such as meth-.
• allyl alcohol and methyl ethyl ethynyl alcohol were also good solvents for the interpolymer.
• the interpolymer could be spun into filaments which on cold drawing yielded oriented fibers of good strength. Molded films of this material were clear and pliable.
• Products possessing properties intermediate between those of the simple polyamides and the above interpolymers were obtained by using varying amolmts of the ingredients mentioned above, namely, fi-aminocaproic acid and hexamethylenediammonium adipate.
• the melting pointcomposition curve for this system passes through a minimum at about 155 C. Clarity and ease of solubility increase as the composition of the interpolymer approaches that possessed by the minimum melting product.
• the table below gives the melting point, as determined for small particles (fibers) on a heated block in air, for fiberforming polymers prepared from various proportions of these two ingredien Melting points of various hexamethylene adip- 5 amide-pOZy-G-aminocaproic acid interpolymers Hemmethylene PoIy-G-amingcapadipamide roic acid Melting point, C. Weight M018 Weight M015 0 0.0 100 100. 0 205-207 l0 5. 3 90 94. 7 176-178 15 8. l 85 91. 9 170-172 2) 11. 1 80 88; 9 165-167 30 17.6 70 83. 4 158-160 40 25. 0 60 75. 0 154-156 45 2o.
• the sheet thus obtained was very transparent, tough and quite pliable.
• the interpolymer which melted at 156-158 C. and had an intrinsic viscosity of 1.06, possessed the same solubility characteristics as the interpolymer prepared with the use of amino acid. It could be spun into filaments. which on cold drawing gave oriented fibers of great strength.
• the interpolymer contained about 5.4% of caprolactam monomer as determined by sublimation methods.
• EXAMPLE III A mixture of 65.5 parts of hexamethylenediammonium adipate, 57 parts of epsilon-aminocapronitrile (B. P. 133 C./30 mm.),- (equivalent to 65.5 parts of the amino acid), and 54 parts of water was heated in a sealed tube in the absence of oxygen for 18 hours at -200 C. and then for 3 hours more at 220230 C. The tube was then openedand heated for 3 hours at 230"- 240" C. under a pressure of 2 mm. The interpolymer thus obtained was a colorless, pseudoresinous tough solid which melted at about 161- 162 C. (in the form of fiber).
• the adipic acid is used in the form of a salt, e. g. sodium adipate.
• a salt e. g. sodium adipate.
• the diamine and dibaslc acid must be used in substantially equimolecular amounts, 1. e. not more than 5% excess of either should be used.
• the ratio of amino acid to diamine-dibasic acid mixture used depends upon the properties of the product desired. This is apparent from the table given in Example I.
• the preferred products from the standpoint of solubility are those in which the molar ratio of amino acid constituent to diaminedibasic acid-constituent (e. g.
• the amino acid ranges from 1:1 to 6:1, or in other words, in which the amino acid constitutes from about 50 to 85 molar per cent of the total polyamide-forming composition, considering the diamine-dibasic acid portion as one constituent.
• the ratio of the amino acid constituent to the diamine-dibasic acid constituent ranges from 1.3:1to 3:1, 1. e., in which the amino acid constitutes from about 55 to 75- moiar per cent of the total polyamide-forming composition, have the greatest solubility.
• the preferred procedure is to carry out the reaction in the presence of water
• other diluents e. g. solvents such as the phenols, partial solvents such as alcohols, or non-solvents such as mineral oil
• solvents such as the phenols
• partial solvents such as alcohols
• non-solvents such as mineral oil
• modifying agents e. g. plasticizers, viscosity stabilizing agents, pigments, etc.
• An antioxidant may also be added.
• the preferred temperature range lies between 180 and 300 C. a
• the interpolymers of this invention are soluble in the solvents (phenols and carboxylic acids) which have a solvent action on polymeric aminocaproic acid and polyhexamethylene adipamide. As indicated in Example 1, they are also soluble in hot alcohols such as butanol and benzyl alcohol, in mixtures of alcohols with chlorinated hydrocarbons, and in unsaturated alcohols. It is surprising that the interpolymer should be so much more soluble than either the amino acid polymer or polyhexamethylene adipamide, for the interpolymer like the individual polymers is a straight chain polymer made up of segments, each one of which contains six carbon atoms. On hydrolysis with hydrochloric acid the interpolyamide yields a mixture of products comprising aminocaproic acid (as hydrochloride), hexamethylenediamine (as hydrochloride), and adipic acid.
• solvents phenols and carboxylic acids
• interpolymers of this invention it may be observed, form a subclass under the broad class of amino acid-diamine-dibasic carboxylic acid interpolymers which form the subject matter of Carothers S. N. 266,014, filed concurrently herewith, and assigned to the assignee hereof.
• the products of this invention are useful in making fibers, filaments, sheet material, films, e. g. for use as wrapping foil and safety glass, molded articles, electrical insulation, felting compositions, adhesive compositions, and coating compositions.
• interpolymers having marked advantages over either the G-aminocaproic acid polymer or polyhexamethylene adipamide in that the present interpolymers have less tendency to crystallize and are therefore readily obtained in the form of transparent films, ribbons, etc.; they melt over a wider range and at a lower temperature; they are soluble-in low boiling solvents and are therefore more suitable for application from solution; and they yield more flexible products.
• hexamethylenediamine as used in the claims includes its amide-forming reactants.
• adipic acid as used in the claims includes itsamide-forming derivatives.
• An interpolymer obtained by polymerizing a mixture of .polyamide-forming reactants comprising hexamethylenediainine and at least two additional amide-forming reactants one of which is adipic acid, and the other of which is a substance of the class consisting of B-aminocaproic acid and its amide-forming derivatives.
• a filament comprising the interpolymer set forth in claim 1.
• a textile lber comprising the interpolymer set forth in claim 1.
• Sheet material comprising the interpolymer set forth in claim l.
• a process for making interpolymers which comprises heating. at reaction temperature a mixture of polyamide-forming reactants comfprising hexamethylenediamine and at least two additional amide-forming reactants, one of which is adipic acid and the other of which is a substance of the class consisting of 6-aminocaproic acid and its amide-forming derivatives; the G-aminocaproic acid constituent in the said mixture constituting from about 50 to 85 molar percent of the sum of the G-aminocaproic acid constituent and the hexamethylenediamineadipic acid constituent, and the components of the last-mentioned constituent being present in substantially equimolecular proportions.
• a process for making interpolymers which comprises heating at reaction temperature a substance of the class consisting of G-aminocaproic acid and its amide-forming derivatives, and a mixture of substantially equimolecular proportions of hexamethylenediamine and adipic acid, and continuing said heating until the polymeric product obtained is capable of being formed into continuous filaments; the said 6- aminocaproic acid constituent constituting from about 50 to 85 molar percent of the sum of the 6- aminocaproic acid constituent and'the hexamethylenediamine-'adipic acid constituent.
• a process of making interpolymers of low lactam content from polyamide-forming reactants one of which is a substance of the class consisting of G-aminocaproic acid and its amidei'orming derivatives, which comprises heating said substance, hexamethylenediamine, and adipic acid, in the presence of water, continuing the heating with retention of water until the major portion of the reactants has combined to form polymer, continuing the heating with removal of water, and then heating the reaction mixture in the molten state under reduced pressure; the G-aminocaproic acid constituent in the said mixture constituting from about 50 to molar percent of the sum of the fi-aminocapro" acid constituent and the hexamethylenediamine- 12.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Proteomics, Peptides & Aminoacids (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyamides (AREA)
• Paints Or Removers (AREA)
• Adhesives Or Adhesive Processes (AREA)

Priority Applications (6)

Applications Claiming Priority (1)

Publications (1)

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Cited By (8)

Families Citing this family (4)

• 1939
  • 1939-04-04 US US266001A patent/US2252557A/en not_active Expired - Lifetime
• 1940
  • 1940-04-04 GB GB6090/40A patent/GB540135A/en not_active Expired
• 1944
  • 1944-05-12 FR FR904239D patent/FR904239A/fr not_active Expired
  • 1944-08-05 FR FR53741D patent/FR53741E/fr not_active Expired

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